The Scientific Method
by Gigabomb
Summary: Vexen x Xigbar. Their elements do not oppose and their research never crosses, but despite this, they clash anyway, as Vexen has never learned how to let go of a grudge, and Xigbar has never learned how to let go of anything that amuses him.


_Author's Note_: This was written for kytha, who ironically provided both the summary and the necessary editing, which resulted in this fic being 1,000 words longer than the original draft. This is the longest one-shot I've ever written, which is kind of amusing considering this is a virgin fandom for me. In other words, if I got the characterizations horribly, horribly wrong, I got thousands of words of characterization horribly, horribly wrong. Just so everyone knows that I am not, in fact, all that original, Xaldin's engineering background, Lexaeus's fondness for botany, and Ienzo having long hair before he lost his heart all are stolen from rabbitprint's KH2 fic.

Vexen's day started out unpleasantly, and further degenerated from there. The first of the nuisances stemmed from the fact that Castle That Never Was still had a tendency to rearrange itself on occasion, even after over five years of residence and a month of Xaldin trying to make a functional ground plan before giving up in disgust. It was for this reason that Vexen found himself tromping down seven flights of stairs at eight o'clock in the morning trying to find the Kitchen of Dearly Departed Egg Timers (as Ansem's apprentice, Xehanort had not been what one would call an exemplary cook, and even Xemnas was still in the habit of overcooking everything he attempted to make by becoming distracted by something else halfway through). Normally Vexen went without breakfast- hardly even noticed his hunger until long past noon- but he wasn't able to locate his laboratory (which he refused to name, just on principle), either. At least in the kitchen there was a chance that at this time of day, someone would be there or in the hopefully still adjacent Dining Hall of Badly Washed Tablecloths (Vexen still wondered what had been in Xemnas's tea that day that had convinced him it was a good idea to let Xigbar title any of the rooms) and he could draft them into assisting him in his search.

That was his plan, at least, and though Vexen couldn't help but despise it on the basis that it contained far too many uncontrolled variables, it was the best he could come up with at this time of day when taking into consideration his cappuccino machine had disappeared along with his laboratory. However, his plan, as ill-thought out and flawed as it was, was still his chosen course of action, and long before anything even happened, Vexen was well prepared to despise anything that prevented him from implementing it.

A pen falling one thousand seven hundred fifty seven feet to strike him on top of the head with enough force to make him stagger certainly qualified. Perhaps using Lexaeus's Inner Garden of Tranquility (now Outer Garden of Tranquility, as it was currently located at the base of the Castle That Never Was; the random castle configuration coming into play again) as a hopeful shortcut hadn't been the wisest move so shortly after the castle had rearranged itself. For all he knew the soil could be hovering over nothing, waiting to crumble away at the slightest application of pressure. But it wasn't a particularly ill-advised idea, either, and certainly didn't account for a pen falling from the highest turret of the castle (which had formerly housed all the equipment to fuel Zexion's astronomy hobby, though Vexen had pointed out to Number Six numerous times that adopting star-gazing as a new discipline was a waste of time in a world without a sky. Far from taking offense as he once would have, all Zexion ever did in return was smile slightly and reply that the darkness held its own points of interest. But that was no longer relevant. It was probably now an offshoot of the Library or something).

For a moment after the pen had made its entirely unexpected appearance, all Vexen could do was stare dumbly at the writing utensil, his plan forgotten, if only for a moment. It now lay innocently on the ground left of his foot, partially hidden under one of Lexaeus's leafier shrubs. A pen. A blue, plastic one.

There had to be some explanation.

As it turned out, there was, and it quickly presented itself in the form of Xigar, stepping out of a newly created darkness rift in front of Vexen with a timer in hand and a visible squint in his one eye. "Hm… well, the estimated drop time is a little low, but I guess we did forget to take into account the wind coming from the new gap between the Tower of Silent Malice and the Pinnacle of Eternal Forgetfulness…"

It was without giving Vexen a second glance that the Freeshooter bent down and retrieved the pen, twirling it between his fingers absently as he continued muttering under his breath, "Still, not as bad as it could have been with the reconfiguration-"

"Xigbar."

Vexen was half sure Number Two would continue to ignore him, but it was with an uncharacteristic amount of alacrity that Xigbar stopped fiddling with the pen and turned to face him. "Yes?"

"You're the one who dropped that instrument?"

Xigbar looked down at the pen in his hand. "This?" Then he grinned, sharply, his (blatantly false, in Vexen's opinion) mask of intellectual curiosity immediately giving way to his usual edged smugness. "No. Xaldin's better at judging wind currents than I am."

Vexen felt his eye twitch. He restrained the reflex with an effort. "May I ask why Xaldin dropped a pen from several thousand feet to hit me on the head with it?"

Xigbar shrugged. "We were originally going to aim for one of Lexaeus's rose bushes, but I thought a moving target made the experiment more interesting. Xaldin had to do some pretty quick calculations to guess where you would be at the point of landing." His grin sharpened further. "I suppose it's fortunate you're so predictable. Never shifted speed or direction at all."

Vexen stiffened. When he spoke again, after a few moments of endeavoring to get himself under control, his tone was laced with ice. "If you insist on continuing with your inane testing trials, I would ask you to find a different target."

Xigbar snorted. "We can't all be chemists, you know. Just because you barely scrapped a pass in physics back in Radiant Garden, you persist in slowing down our scientific advancements."

"Which include attacking me with writing utensils?" Despite himself, Vexen could hear the venom entering his voice.

Xigbar noticed. His casual slouch against a nearby apple tree (which Lexaeus had somehow engineered to bear fruit year round; no one else knew exactly how) was carefully executed in such a way that the Freeshooter knew it would set Vexen on edge. His yellow eye practically gleamed with barely concealed amusement. "Well, Vexen, you know as well as I do that some sacrifices must be made in the name of-"

It was, perhaps, slightly beneath him to hiss a retort at Xigbar. Number Two wasn't nearly worth the effort. He certainly wasn't worth sticking around to trade barbs with when Vexen still hadn't properly started his day. It was on that thought that Vexen turned and stalked out of the garden, though Xigbar's voice stilled him at the threshold.

"Hey, Vexen. What are you doing here, anyway? You looking for something?"

Vexen paused. Xigbar might… but no. The Freeshooter had never been anything but a thorn in his side, and that was unlikely to change now. "No."

Then he left, though he continued to feel Xigbar's gaze on him long after he left Number Two's line of sight.

Vexen never did find his laboratory that day, despite commandeering Number Nine's assistance when he came across Demyx looking lost in a hallway. He ended up spending the majority of the time nursing a headache from the Melodious Nocturne's incessant chatter and the rest of it eating a strangely rubbery egg salad sandwich (the Superior really should have been banned from the kitchen) while reading one of many academic journals Lexaeus had come across during his last expedition into a new world they had discovered. The article he had flipped open to on a whim was a treatise on mining valuable minerals while setting up proper safety equipment for possible dangers (hags and poisoned apples were a frequent footnote). Not nearly Vexen's area of expertise, but then, all the books that pertained to his interests were in his laboratory, and this was, if nothing else, better than nothing. But not much better.

And even though Vexen knew it was quite possibly the least scientific conclusion he had ever reached in his life, somehow the complete waste of his day was entirely Xigbar's fault. He had little evidence, no line of inquiry, and his reasoning was faulty at best, but for once Vexen couldn't bring himself to care in the least.

Xigbar would pay for this.

----

The problem with swearing revenge on someone (or rather no one, but then the grammar was incorrect) like Xigbar was this: there wasn't much anyone could do to him. The Freeshooter didn't have any possessions he was particularly attached to except his guns (which were impossible to vandalize), he didn't resent getting sent out on three world expeditions in a row, even when one of them was to Atlantica with Demyx and the other two were with Axel (who was almost as obnoxious as the Freeshooter himself, and in addition had a tendency to set random pieces of other people's clothing on fire when bored; this was often), and Vexen hadn't the faintest idea of what constituted an appropriate prank. Mostly because pranks were childish and a complete waste of time.

In the end, however, childish was all that Vexen could come up with, and he did admit to some petty satisfaction when it was Demyx's turn to make dinner and Vexen mixed some (very finely chopped) peanuts into the chicken curry when Number Nine wasn't looking. The satisfaction was further magnified when the allergies of one's Other proved to pass on even after losing one's heart and Xigbar's face swelled up to such proportions that he had to leave the dinner table less than ten minutes after everyone had sat down to eat. The satisfaction was so magnified, in fact, that when the Melodious Nocturne, puzzled, watched Xigbar rush out of the Dining Hall of Badly Washed Tablecloths, then turned back to the general assembly and said mournfully, "I thought Xigbar_ liked _curry," it was all Vexen could do to keep his expression straight and not snort into his napkin.

It wasn't really enough punishment for wasting Vexen's time, especially taking into account that one of his Bunsen burners had boiled over while he was absent from his laboratory and the spaghetti had been ruined (so much for planning out his turn to make dinner in advance), but it was at least some reparation, which was more than he usually received when it came to Xigbar. It was on that thought that Vexen returned to his usual schedule (which included thinking about the Freeshooter as little as possible instead of using every waking moment to contemplate how to get Xigbar to fall into a pit of acid without being identified as the culprit- a difficult undertaking, considering he was the only one with large amounts of corrosive chemicals on hand at all times) satisfied.

His state of contentment didn't last long. There was a slight chance this was because Xigbar had found out who had dumped the peanuts in Demyx's curry, but that was unlikely, as such things were inevitably pinned on Axel when Xigbar himself wasn't a possible suspect. There was a much larger chance it was because the Freeshooter had finished his joint experiment with Xaldin calculating the new wind currents around the Castle That Never Was and, since Lexaeus and Saix were ones on world expedition duty for the week, had nothing productive with which to occupy his time. Which meant he inevitably decided to waste someone else's.

Back in Radiant Garden, Even had always been Braig's favorite mark for pranks, but the eldest of Ansem's apprentices hadn't been discriminatory and always made a point of varying his targets according to his mood. Braig's rather haphazard method for selecting his victim had, once upon a time, resulted in the painful I-swear-I-didn't-know-Xehanort-couldn't-identify-poison-ivy Incident, the bizarre I-have-no-idea-why-Elaeus-thinks-he-has-the-Black-Plague Incident, and the extremely memorable Ienzo-never-told-me-he-was-scared-of-bats-yes-sir-perhaps-we-should-have-stored-them-somewhere-other-than-his-closet Incident. The amount of 'incidents' Even alone had been through were far too numerous to list. Only Dilan, as Braig's accomplice of choice, had avoided the majority of the consequences of Braig's decidedly twisted sense of humor, and even he hadn't been able to escape when someone who had just finished his paper on economics in hunter-gatherer societies early dumped a laxative into the oatmeal.

But Xigbar wasn't Braig. Xigbar, for whatever reason, hadn't bothered tricking Xemnas, Xaldin, Lexaeus, or Zexion into doing something stupid since the first year of their inhabitance of the Castle That Never Was. Vexen, as his Other had been, was still Xigbar's prime choice for a prank, but the Freeshooter now focused what time he had left after stealing all of Vexen's left gloves and doing real work (as rare an occasion as that was) on the neophytes. Why this was, Vexen didn't know, and he really didn't care, especially after he went into his glove drawer one morning about two weeks after the Castle That Never Was reconfigured itself and moved his laboratory to the third floor (which Vexen resented on the basis it had been fine in the basement and now was distressingly close to the Common Room of Incessant Procrastination where most of the more sociable members of the Organization resided when they had nothing better to do) to find that all of his left gloves were missing. In their place was a small sheet of paper, where in a scrawl easily recognizable from years of deciphering lab notes with nonsensical abbreviations, someone had written, _good thing you're ambidextrous_. The idiot hadn't even bothered to capitalize the G.

Vexen felt his mouth tighten into a thin line. His (ungloved, thanks to that poor excuse for a Nobody) hand curled around the note, crumpling it into a ball. Unlike the others, who merely wore the gloves as a part of the uniform, Vexen _needed _his. He'd experienced enough chemical burns from Even's occasional carelessness to know that. And Xigbar knew it as well.

Vexen hadn't known for sure that the Freeshooter would be in the Common Room of Incessant Procrastination. Though Number Two certainly qualified as a more sociable member of the Organization, he was also rather fond of high places and spent much of his free time perched on the roofs of the castle's towers. However, half the reason Xigbar played pranks was for the reaction on the part of his target, meaning he'd want to be somewhere Vexen could find him.

As usual, Vexen's hypothesis was entirely correct. Sitting in one of the common's rooms reclining chairs with his feet propped up on the nearby table, Xigbar wasn't even bothering to pretend he was doing anything other than waiting for Vexen, with his hands behind his head and humming (badly out of tune; he was as tone deaf as his Other) a ditty under his breath. As Vexen walked through the darkness rift he created, the Freeshooter's humming trailed off, and he grinned at Vexen. "Hey. Don't see you in here often. Did you lose something?"

Vexen's eyes narrowed. "I didn't lose anything. You stole all my left gloves."

Xigbar raised a mocking eyebrow. "I stole something of yours? Funny, I distinctly don't remember _stealing _anything…"

Vexen gritted his teeth. Even after he had had his fun, Number Two still insisted on his asinine games. The worst part was the only way to get him to stop was to play along. "Fine, you _borrowed_ all my left gloves. I want them back. I have work to do."

Xigbar's grin widened, and he leaned back further in his chair. "Say please."

Vexen's hands clenched. But sometimes the Freeshooter's games went too far. "_No_. Return my gloves or I'll report you to the Superior for impeding my progress." He allowed himself a thin smile, stemming from emotions that weren't really there. "Considering what I'm working on, I doubt he'll be pleased."

Xigbar actually blinked at the clear threat in Vexen's voice. "Man, you must be pissed to be willing to go crying to Xemnas. Usually you have a little more pride than that."

Vexen didn't reply. Didn't say anything about what could Xigbar possibly know about pride. Provoking Number Two led no where. Experience alone could tell him that, even if he had never possessed the sense in the past to rely on old encounters to guide his dealings with the gunner. He was tired of playing Xigbar's games.

After a moment, the Freeshooter sighed and rubbed the bridge of his nose. "Alright, alright. They're on the top shelf in your closet where you store all the stuff you never use but refuse to throw away because you're such a packrat. I only moved them like five feet."

He had gotten what he wanted. So Vexen left. He ignored the expression on Xigbar's face as he turned and walked through a newly summoned darkness rift, the look that said that he hadn't gotten what he expected, and what he had received instead was something entirely unpleasant. Perhaps if the Freeshooter didn't get the reactions he wanted, he'd shift his attention to something else, and leave Vexen in peace.

----

The gloves were where Xigbar had said they would be, and Vexen didn't let himself brood over Number Two's persistence in acting frivolous. His work required too much concentration to let his focus be diverted by something as trivial as the Freeshooter's irritating behavior.

He returned to his room that evening only to discover that though he had dismissed Xigbar from his thoughts, the other Nobody hadn't had the courtesy to return the favor. This conclusion was reached from the fact that the door leading from his bedroom to the hallway was missing. Not even the hinges were left.

The only saving grace was that at least Xigbar wasn't so inconsiderate as to remove Vexen's door by ripping it off the frame. There was clear evidence that Number Two had, at least, bothered to use a screwdriver. Which meant that the door could be replaced with relative ease, but first he had to find it, and, by extension, Xigbar.

Vexen stared at the gap in the wall where his door had used to be and wondered if he really cared if Xemnas knew that he was the only one in the Castle That Never Was with large amounts of acid. Surely being put on permanent probation for killing a fellow Organization member would be worth it if it meant he never had to deal with Xigbar ever again. The Freeshooter hadn't even bothered with a _note _this time.

Vexen was exhausted. He had been working for the past twelve hours, and if anything else had been taken (up to and including his bed- he could stand the sofa for one night), he would have put off looking for Xigbar until morning. But Vexen knew that without his door, his own innate unease at being exposed would never let him get to sleep. Which Xigbar knew, which was probably exactly why he had taken it.

The Castle That Never Was possessed more than three hundred rooms (exact numbers varied depending on the castle's mood), but fortunately Xigbar was, if nothing else, something of a creature of habit, regarding where one could find him at certain times of the day if not what he might be doing at any given moment. Since the Freeshooter could hardly lug the door up to the roof of one of the towers (or rather, he could, but was too lazy to bother with such an enterprise), there was really only one other place he was likely to be this late in the evening.

The Library of Misplaced Bookmarks wasn't, as it happened, called that very often. Most of the time everyone just pronounced the capital L. Vexen had once argued with Zexion for about half an hour about why this was before they finally determined that as it was by far the most important room in the castle (though some of the more illiterate neophytes- i.e. all of them- disagreed with this statement), the Library had a name only a formality. It didn't really need one. It was, after all, the Library.

Xigbar, as uncultured and boorish as he occasionally acted, had been one of the apprentices of Ansem the Wise (or rather, his Other had been), and that meant that whether he wanted it or not, a deep appreciation of books had been thrust upon him, if only from long-term proximity. Even though that manifested itself with a strange obsession with manuals on weapons maintenance when Xigbar wasn't doing research for one of his projects, it couldn't be denied that out of all the original six, the only one who liked to read more for pleasure than Xigbar was Xemnas (whose favorite books were, in Vexen's opinion, even more uselessly frivolous than the Freeshooter's. Why the Library even had a poetry section, he'd never know).

Vexen didn't know whether to feel surprised or irritated that upon opening a darkness rift into the Library, he almost ran straight into his bedroom door, which was propped inconveniently against the bookshelf that contained, at Lexaeus's insistence, several hundred volumes on horticulture.

Several feet away on a window seat looking out over the main plaza of the World That Never Was sat Xigbar, apparently engrossed in a magazine depicting several dozen types of gunblades. After five seconds, during which Vexen waited for Xigbar to look up and acknowledge him and the Freeshooter completely failed to do so, he reached out and yanked the magazine from the other Nobody's hands. Then he threw it on the floor. Then he stomped on it a few times, just for good measure.

Xigbar, who usually had some of the fastest reflexes of any of them, spent the time he would have normally used to grab the magazine back staring bemusedly at Vexen. Then he looked at the gunblade magazine (somewhat worse for wear after making acquaintance with Vexen's boots several times) on the carpet. When he finally returned his gaze to Vexen, the Freeshooter looked as if he wasn't sure whether to be angry or amused. "That was an interesting display of pent-up aggression. Did your parents not give you enough attention as a child or something?"

Vexen ignored the question. "First you took my gloves. Then later in the same day you steal my bedroom door. If you are really so bored as to be able to find nothing to do but torment me, I suggest you go and ask the Superior for a long-term assignment as far away from the World That Never Was as possible. Perhaps by the time you return I will have reconsidered poisoning the water pipeline leading to your room."

At that, amusement asserted itself as the dominant expression on Xigbar's face. He was also looking far more pleased with himself than Vexen thought the situation warranted. "I suppose that means you didn't notice I redecorated your bathroom in a tasteful orange while I was taking a break from unscrewing the door from the wall. For a scientist, you really aren't all that observant-"

It wouldn't be entirely accurate to say that at that moment, something inside Vexen snapped. For one thing, he hated that analogy, and for another, Vexen could admit to himself, if no one else, that his was a naturally brittle temperament. His threshold for unexpected changes, for any sort of humiliation whatsoever, no matter how minor, was well below the average. He maintained his self-control rigidly, but Vexen could remember how easily it had been for Even to be pushed too far. And lack of emotions or not, the difference between a Nobody and his Other on occasion could prove to be virtually nonexistent.

That being said, Vexen couldn't recall any incident in the past where Even had come at all close to hauling off and slugging Braig in the jaw. So perhaps there was a difference after all.

Not that Vexen punched Xigbar. He wasn't about to chance hurting his hands just for the chance to see the Freeshooter bleed. Still, grabbing Number Two by his coat, hauling him to his feet and slamming him against the nearest wall proved nearly as satisfying, mostly because of the blatant shock that ran across Xigbar's face when his back hit the stone with an audible thump.

On the rare occasions when Vexen sparred, he never fought with physical force, preferring instead to use his ice magic and fight at a distance, bringing his shield to bear only when his opponent on the rare occasion stopped blocking long enough to counterattack. It was therefore hardly surprising Xigbar had apparently forgotten that despite Vexen's distaste for violence, pound for pound he was not only heavier than the Freeshooter but a full inch taller. Considering the situation, Vexen was more than willing to use his superior height to his advantage, putting his face close to Xigbar's and hissing through his teeth, "I don't care about your reasons. Stop using me as your convenient target for pranks. I'm not the only one in the castle. Go after someone else for a change next time you're finished with work and _leave me alone_."

Xigbar looked at back at Vexen, his composure recovered after his initial surprise and his eye now narrowed in what was probably annoyance. Then he grinned.

It was then that Vexen somewhat belatedly remembered that though he may have been larger than Number Two, his military training was somewhat lacking in comparison. It was in something less than three seconds that he found himself with his face being ground into the carpet and his arm pulled painfully behind his back, the weight of the Freeshooter settling itself on his lower back. For a moment, there was silence.

"You know," Xigbar said conversationally as he shifted himself into a more comfortable position, "I was kind of hoping for a better reaction than the one you gave me this morning, but this really takes the cake. I didn't actually expect you to lose it." He slightly loosened his grip on Vexen's wrist, though not nearly enough for Vexen to have any hope of throwing the Freeshooter off. "And for the record, I didn't actually paint your bathroom orange. I was messing with you. You should really look up what that means sometime."

Vexen grunted. He would have elaborated, except he was currently having trouble getting any air into his lungs.

He couldn't really see in the position Xigbar had manhandled him into, but somehow the quiet that followed the Freeshooter's short statement came across as… considering. It proved itself to be so when after a short pause, Xigbar in an uncharacteristically somber tone of voice said, "None of the others react right."

Vexen, after a few moments of (mostly futile) struggling, managed to maneuver himself so it was his cheek being smashed into the ground instead of the whole of his face. It made breathing easier, and at least now he could see. And he had to admit that now his scientific curiosity had been aroused, if only slightly, but Xigbar's ambiguity. "React right to what?"

Xigbar shrugged. "To anything." He smiled again, but this time there was something distinctly absent from the expression. "I know you aren't as oblivious as you act. You can't tell me you haven't noticed."

Vexen scowled. The position he was in was rapidly becoming extremely uncomfortable. "I have no idea what you're talking about."

Xigbar snorted. "Oh, come on. I see you getting frustrated these days when you try to argue with Zexion or Xemnas. Hard to get them passionate about anything anymore, isn't it?"

Vexen opened his mouth to retort, but the words died on his tongue. He had to struggle with himself for a few seconds before he finally got out, "We lack hearts. It only makes sense that we no longer feel things as strongly as we used to. And if you're going to insist on discussing this, you will have to let me up first. I am not going to talk with someone who currently has me pinned to the ground."

Xigbar did so with surprisingly little protest, letting go of Vexen's arm and pushing himself to his feet to lean against the wall where Vexen had shoved him just a few minutes before. Vexen himself shifted into a sitting position and rested his weight against the horticulture bookcase. A quick examination of his arm proved that beyond some slight strain, there was no permanent damage done.

Xigbar was looking down at him now, and Vexen was suddenly uncomfortably aware that he had just put himself in the subordinate location. However, for once Xigbar didn't seem inclined to press his advantage. "I know we don't have hearts. Xemnas rambles about it often enough. But still, it's kind of unnerving to put pink dye in Zexion's shampoo and have him come out the next morning and act like his new hair color doesn't bother him at all. You remember back in Radiant Garden, how proud Ienzo was of that mane of his. If I had done that to him back then, he would have thrown a fit and then not talked to me for a week. Now…" he shrugged. "It's not really worth it, when there's no payoff. You're the only one who reacts at all anymore." He grinned crookedly. "I've got to admit, when you were so cold this morning, it freaked me out. Made me think I had lost the only halfway worthwhile victim left in the entire castle."

Vexen stared up at Xigbar in disbelief. "_That _is your reason for stealing something of mine twice in one day? I didn't respond to your specifications the first time?"

Xigbar glanced at the ceiling in thought. Then he nodded, amusement coloring his face yet again. "Yeah, that sounds about right."

"But I lost my heart along with everyone else," Vexen felt obliged to point out. "I am not the same person as Even was."

Xigbar rolled his eye. "I know that. But Even was so repressed that he acted like he didn't have emotions most of the time anyway. The shift between having a heart and not having one didn't seem to be as big a deal for you as it was for the others."

Vexen crossed his arms, then quickly uncrossed them as his shoulder quickly reminded him it wasn't quite ready for anything that at all resembled moving. "That is the most idiotic hypothesis I've ever heard. And besides, if the contrast between how the rest of the original six act now in comparison to how they acted in Radiant Garden unnerves you, use the neophytes as your targets. You certainly spend enough time with them that I'm sure you already know how best to set them off."

Xigbar choked back a laugh. "You're kidding, right? Look at my options. Depending on the time of the month, Saix would either rip out my spine or go complain to Xemnas, Axel _sets things on fire_, Demyx sulks whenever anything does anything to him he thinks he doesn't deserve, and Luxord's the only one who will remember to buy booze when he goes out on missions. If I did anything to him, he would cut me off for sure."

Vexen scowled and shoved himself to his feet. "Those reasons are incredibly shallow and I'm not having this conversation anymore. And if you prank me again, I am going to-"

Xigbar raised his hands in a placating gesture. "Don't worry about it. I've had my fun. I'll leave you alone for a while."

Vexen nodded stiffly and turned to go, picking up his bedroom door as he did so. Before he managed to summon another darkness rift and return to his room to finally go to sleep (no chance he was repairing the door tonight. Icing over the doorway would have to do for the moment), Xigbar's voice again intruded. "Just… one more thing. In those rare moments when you actually deign to interact with the rest of the Organization, watch how they act. Maybe you'll finally notice what I did four years ago."

"I'll consider it." Then Vexen left, his shoulder still aching and carpet indentations carving an interesting pattern in his face. This had not been a good day.

----

Vexen hadn't actually intended to try out Xigbar's suggestion and observe the interactions of the other members of the Organization, but inadvertently he found himself doing so anyway. As it turned out, for once in his life, Xigbar was right. The way the Nobodies acted around each other were slightly… off. Not only in contrast to their former selves (as Vexen had no basis for comparison with the neophytes), but in relation to how regular people, people with hearts, interacted with each other. It wasn't only because of a lack of emotion, either. The capacity for empathy was lost. Words were misinterpreted, meanings were garbled, as they once never would have been. There was no longer understanding, and though it was difficult to take offense without a heart, it wasn't impossible. Unnecessary tension was rife throughout the Organization, something Vexen knew he should have noticed years ago. But then, he had buried himself in his work, rarely talking with the other Nobodies or even collaborating on projects, something Ansem's other apprentices would never have tolerated in Even, but a state of affairs the other Nobodies were more than willing to accept when concerning Vexen.

Xigbar, despite being the one to bring up the issue, was no exception to this. The Freeshooter's mockery was harsh when Braig would have tempered it with a friendly grin, and there was no longer the underlying feeling that came across even when Braig had been at his most vicious, the one that said _I am not trying to hurt you. We're okay, aren't we? _And it had always been. But no longer.

Still, mere observation couldn't really substitute for testing within a controlled environment. Which was why Vexen found himself cornering Zexion one day in the new (for the old one had been transformed into a bathroom during the reconfiguration) Astronomy Tower of Why Doesn't Our Heating System Extend Up Here. His reasons for choosing Zexion as his test subject were threefold: one, out of all of Ansem's former apprentices their fields of expertise corresponded the most, so Vexen could actually manage come up with a conversation topic without too much effort; two, out of the original six Nobodies, Zexion's Other had been the youngest and the least able to control his emotions (if in fact there were any to control); and three, again out of the original six Nobodies, Number Six, as the one with the absolutely least combat training, was the only one who Vexen knew he could actually take a punch from if the Cloaked Schemer was pushed too far during the course of Vexen's test and tried to deck him.

However, though point one proved definitely to lean in Vexen's favor, as Zexion was more than willing to discuss at length his progress in discovering the exact composition of the darkness surrounding the World That Never Was, points two and three didn't turn out to be quite as helpful. Mostly because Zexion completely failed to lose his temper no matter how hard Vexen tried to provoke him.

Some of this may have had to do with the fact that Vexen had never made a point of riling people on purpose in the past and didn't know how to go about it, but much of it, Vexen began to fear, was actually because Xigbar's theory didn't have any flaws in it. For the first few months after their hearts had been taken from them, Ansem's former apprentices hadn't seemed much different from before, but that had been because they reacted to things from the memory of how they had felt in similar situations in the past. But it had been five years since then, and those memories had begun to fade.

It was in desperation that Vexen tried the one thing that, back in Radiant Garden, had been guaranteed to make Ienzo start frothing at the mouth. That is, questioning the use of his current pet project. "As… interesting as this is, I hardly think we need to know the nature of darkness at this point, Zexion. Shouldn't you be concentrating on something that can actually be of assistance to the Organization's goals and stop wasting time?"

Vexen did his best to adopt what Braig had once called Even's 'stick up his ass' voice, which, even with the perhaps not as derogatory as it could have been dismissal of Zexion's project, should have been enough to at least make Number Six's eyes narrow. But no. All Zexion did was smile in a serene sort of fashion that would have looked ridiculous on Ienzo and reply smoothly that he was sure darkness played a part in why their hearts had been taken and that it was best to find out such things before they became a concern.

Vexen had left the astronomy tower a few minutes later, making excuses that sounded false even to his own ears but Zexion accepted with a calm nod before returning to his telescope. Vexen didn't bother with any more tests after that. On this occasion, one trial had proved more than enough.

He couldn't say he was all that surprised when about a week after the encounter in the Library, Xigbar made an appearance in his laboratory. Normally all the members of the Organization- even the neophytes- had the good graces to not open a darkness rift into his private sanctum, but Xigbar apparently had no compunctions against doing so, even if he did have the sense to open the rift at the doorway instead of somewhere where he might have interrupted an experiment.

Vexen didn't acknowledge the Freeshooter immediately, the turnabout granting him a brief moment of amusement before it faded away, as all feelings did so easily now. His back to Xigbar, Vexen continued his current experiment, mixing together Heartless remains and what little the lesser Nobodies left behind after they died. Nothing materialized, no corpse, no soul, but then, hearts were hard to quantify. Vexen wasn't entirely sure what Xemnas expected to get out of this. It would be much simpler to build a heart from scratch then try and mix parts of deceased beings together and expect to get an encouraging result.

There were other components to work with, but Vexen knew the end product (absolutely nothing) would be the same no matter how many tests he ran, so he pushed his protective glasses higher on his head, pulled off his gloves and put them next to what Nobody fragments remained, and only then did he turn to face Xigbar. "Going back on your word already?" He was not, perhaps, as irritated as he might have been. At least the Freeshooter hadn't broken anything yet.

Xigbar shrugged, his arms hanging loosely by his sides in a way that made Vexen remember how Braig had refused to wear clothing that didn't possess pockets, and that on more than one occasion he had tripped and failed to catch himself because he hadn't been able to free his hands quickly enough. Dilan had made jokes about that habit leading to more injuries than every single other dangerous hobby of Braig's combined. Those jokes were no longer relevant, but even if they had been, Vexen held a suspicion that Xaldin wouldn't feel the least desire to make them. "I just got back from a world expedition an hour ago." Then the Freeshooter grimaced. "There were singing mice. It was all I could do not to stomp on them. The fairy godmother had some pretty neat tricks, though. I don't think even Ansem the Wise could transform someone into a tree. Good thing Demyx bounces back so easily from stuff like that."

"And you decided, having conveniently forgotten that you said just a week ago that you would leave me alone, that visiting me while I am working was a better idea than finishing up your report."

Xigbar grinned and walked over to Vexen, stopping only a few paces away. "I've got all day to do that. And I was thinking to myself earlier, 'Xigbar, does anyone actually _know _what Vexen does in his laboratory all day? He might have already figured out the answer to all our problems and just not told us like the stuck-up bastard he is.' And of course, I couldn't possibly chance that."

Vexen narrowed his eyes at Xigbar's distinctly unflattering descriptor. "I'm doing some research for the Superior, if you must know. And if that is quite all…"

He trailed off. Something in Xigbar's expression told him that that wasn't nearly all. This proved to be true when the Freeshooter sauntered past Vexen and seated himself on the nearest lab table. It was, like all the others, created from the highest quality of steel. It was also like all the others in that it was intended for laboratory work, not for sitting on. Merely touching it with bare hands was enough to contaminate it. Vexen winced at the thought of some of his test subjects coming in contact with such a thing. He'd have to have a dusk sanitize it after Xigbar left.

"You know," Xigbar said conversationally and without preamble, "As the only two of the original six who haven't completely lost the instinct to express emotions we don't actually feel, I think it would be a good idea if we worked jointly on a project to discover just how much the heart actually dictates our day-to-day behavior."

"Zexion already ran that experiment," Vexen felt obliged to point out. "Besides that, if you want to test the reality of Nobody emotion, you would be better served persuading Demyx to assist you. He still persists in believing he truly feels things instead of just remembering that he felt them."

Xigbar snorted and drummed his fingers on the table, making the metal vibrate slightly under his touch. "Well, Zexion did a crappy job. All his conclusions were based on purely theoretical conjecture. He didn't bother with the practical side of it at all. And you know as well as I do that Demyx has no scientific training to speak of. He couldn't make a sufficiently precise observation if his existence depended on it."

Vexen didn't move. "I don't have time for another project."

"Xemnas will forget that he asked you to work on this one soon enough."

"You and I have never worked together on a long-term basis. In the past we have always proven to clash on method."

"We don't have hearts anymore. That means we could probably work it out without tearing each other's heads off."

"The project doesn't have any immediate relevance."

"Yes, it does."

Vexen frowned. "How?"

Vexen didn't entirely understand what point Xigbar was trying to make when the Freeshooter reached over and grabbed him by the shoulder, pulling him into a proximity that once a upon a time, Even would have hated. But Vexen wasn't Even, and he met Xigbar's gaze evenly as the other Nobody, his nose less than six inches from Vexen's own, stated in a factual tone of voice, "It's relevant in that I've waited a week to do this, and delaying any longer would result in me losing it and dumping several gallons of glue over everything in that gigantic walk-in closet of yours."

Vexen briefly contemplated what it would be like to clean that mess. It was an unpleasant thought. "I suppose that would be unfortunate." Vexen wasn't Even, even if he did retain many of his Other's habits, and since he had lost the vast majority of his self-consciousness along with his heart, he hardly felt awkward at all about grabbing Xigbar by the chin and bringing the Freeshooter close enough to kiss him on the mouth.

If Xigbar still hadn't had one hand on Vexen's shoulder, at that point he very well might have fallen off the edge of the lab table, but as it was, all he did was flail slightly before regaining his balance and kissing back.

Vexen still wasn't sure what the point of this was, but it was still slightly gratifying the way Xigbar shivered as Vexen pulled him closer and nudged open the Freeshooter's lips with his tongue.

And then Xigbar started moving backward, his hand still on Vexen's shoulder, forcing Vexen to move with him in order to maintain contact, and the lab table really was hopelessly soiled now, what with the way he had to brace his bare hands against its surface just to keep from falling over. And then he was bent completely over the Freeshooter, his knees resting on either side of Xigbar's waist, the other Nobody leaning on one elbow in what looked like a distinctly precarious position before finally removing his other hand from Vexen to stay balanced, the kiss deepening all the while until Vexen contemplated the possibility of Xigbar not possessing a gag reflex.

It was then that he broke the kiss, pulling away despite Xigbar's glazed expression and more than slightly confused scowl. "What the hell are you doing?"

"I was wondering the purpose of this phase of the experiment."

"Oh for- research. Whatever. But if you stop kissing me again I'll bite you."

Vexen frowned, considering. Then he nodded. "Very well."

Leaning all of his weight on the other Nobody, forcing the Freeshooter to lay prone on his back without even his elbows to support him, was perhaps unnecessary, but for all that Vexen wasn't Even, he still wasn't about to let Xigbar gain the upper hand. Vexen had seen all too often in the past what happened when the Freeshooter took the lead in the beginning stages of a new project. The other Nobody's methods were far too arbitrary to form a good foundation for the rest of an experiment.

And it wasn't like Xigbar was objecting either, though the other Nobody's hips bucked as Vexen ran a hand down Xigbar's chest and undid the zipper of his coat.

"Damn it, move faster than that, Vexen!"

As he absentmindedly tugged off the other Nobody's shirt (Xigbar being obliging for once and putting his arms above his head to simplify the task), Vexen considered that alternative. He just as quickly disregarded it. It was better to take extra time when researching new fields of study. "No."

The Freeshooter might have objected further, but whatever arguments he might have come up with quickly gave way to the feeling of Vexen's tongue running along the flat plane of his stomach.

Not that Xigbar wasn't able to get a word in edgewise. He certainly made enough noise when Vexen moved his mouth across one of the Freeshooter's more prominent scars.

"Hnn…"

Vexen smiled, pausing briefly in his ministrations, upon which Xigbar immediately made a low-pitched whine, his hands curling and uncurling into fists in protest. He knew that however much Xigbar might complain later, the thorough approach was almost always the best one to take.

----

"For a guy who spends as much time alone as you do," Xigbar said sometime later, his body glistening with drying sweat as he pushed himself into a sitting position and stretched out his arms, his clothing lying in wrinkled piles on the laboratory's floor tile, "You sure are kinky. I'm pretty sure that second thing you did with your fingers would have gotten you jail time back in Radiant Garden."

Settled with his legs crossed on the other end of the lab table, Vexen rolled his shoulders, and frowned at the twinge that still remained from the Library encounter. Unlike the other Nobody, his body temperature had never risen to a point high enough that it made perspiration necessary. The advantages that a mastery of ice magic bestowed upon its user really were boundless. "Interactions with others don't dictate one's preferences when it comes to such things. And as far as I know, the World That Never Was has no laws regarding sexual practices."

Xigbar smirked. "I should certainly hope not. This world doesn't have the thousands of years of history that would spawn something as barbaric as laws that dictate what people do in bed." Then he pointedly glanced around. "Or on lab tables, I guess."

"Very true." Vexen's frown deepened as he followed the Freeshooter's lead and examined the room. Forget about having the lab table sterilized, he was going to need to have the entire laboratory disinfected. "This turned out a great deal messier than I anticipated."

"Yeah, well," Xigbar said with no visible contrition, "Sex usually is. And better that it's messy than it isn't. If you didn't have that lubricant handy- and no offense, but I don't really want to know what it was originally intended for- it wouldn't have been all that much fun. This was pretty good for a first go." Then he grinned, satisfaction practically radiating from his skin. "And I've got to say, even if the thing with the fingers is outlawed on several worlds, the guys who passed those statutes really didn't know what they were missing."

"Mm."

For a moment, there was an uncomfortable silence, and for once it wasn't only on Vexen's end, as Xigbar's smile grew visibly awkward. "Ah… you know, the sex really was nice, but we should probably do some other sorts of tests, too. You know, since I don't think the heart has much to do with how good someone is with their tongue."

Vexen raised an eyebrow. "Such as?"

Xigbar shrugged. "Hell, I don't know. Daily interaction, tolerance for certain sorts of people and situations… coming with me to the Land of Dragons when I go there on Thurday for a reconnaissance mission. You could meet me at the capital's front gates around six. I know you like Chinese food, and the Mushu Pork at this one restaurant is awesome."

Vexen frowned. "Hmm…"

Xigbar raised an eyebrow. "Was that a good 'hmm' or a bad one?"

"… How is their duck?"

At that, the Freeshooter's uncharacteristic discomfort vanished. His smile shifted into something decidedly more assured. "You'll just have to come with me and find out, won't you?"

Vexen considered this. "I suppose it is best to vary our testing trials as much as possible. Limiting them too much would render out project useless."

"… That's a yes, right?"

Vexen nodded. "But make it seven, not six. I have some research to do that day that might take longer than anticipated."

Xigbar's grin turned slightly rueful. "Man, you're picky." Before Vexen could object to this, the other Nobody leaned over across the expanse of the lab table and kissed him, quickly. By the time Vexen could figure out what Xigbar meant by _that_, the Freeshooter had snatched his clothing off the floor, summoned a darkness rift, and left, though not before shouting over one shoulder, "Front gate of the capital of the Land of Dragons at seven on Thursday. Don't forget if you don't want me painting your bathroom orange for real this time!"

Then he was gone. Vexen watched him go, not sure whether to feel irritated or amused. Or whether he felt anything at all.

He decided he did, even if it was only a memory of when he could truly feel emotion. It could, after all, just be a distinction without a difference. And if this project proceeded as planned, he would soon know the truth.

Not that collaborations with Xigbar ever proceeded as planned. However, unlike prior instances when an experiment didn't seem like it would work out exactly as he wanted it to, Vexen couldn't really bring himself to mind. It could never be entirely a waste of applied energy, if it meant that Xigbar had finally found something worthwhile (that _didn't_ involve stealing Vexen's possessions) with which to occupy his attentions. And Vexen supposed it couldn't hurt if it meant he got some decent Chinese food in the meantime.

Now, where had Xigbar thrown his pants…

_END_


End file.
